Self-utilization of indigenous materials in plateau areas: Peroxymonosulfate activation by manganese modified barley straw biochar for efficient degradation of enrofloxacin

In this study the indigenous materials in plateau areas were used to cope with the challenge of increasing antibiotics pollution in Qinghai-Xizang Plateau. The barely straw was chosen as the raw material to prepare the manganese modified biochar (XBSMBC) and then combined with peroxymonosulfate (PMS) to set up the PMS/XBSMBC system to treat the enrofloxacin (ENR) in water. The study showed that there was a higher PMS activation and thus ENR degradation of the manganese modified biochar prepared from the barley straw than those from Xizang wheat straw and Henan wheat straw. The preparation parameters of the XBSMBC, including the mass ratio of barley straw to manganese and the pyrolysis temperature, for the PMS activation as well as the ENR degradation were reviewed and found that the 1:1 and 900 °C were the optimal preparing conditions (XBSMBC-900 (1:1)). The influence of the XBSMBC-900 (1:1) additive amount, PMS dosage and solution initial pH on the ENR degradation was also ascertained. Results of quenching experimental studies and electron paramagnetic resonance demonstrated that ENR degradation in the PMS/XBSMBC system was achieved by a combined effect of SO₄^·-, ·OH, ·O₂^- and ¹O₂. Four possible pathways of ENR degradation were provided, and the toxicity analysis predictions were applied to infer the validity of the PMS/XBSMBC process for the ENR solution treatment.